JPH0817350B2 - Optical branching device and optical transmission line network - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical branching device and an optical transmission line network which are used for an optical transmission line network using an optical fiber cable and which switches the transmission lines.

[Conventional technology]

In order to construct a bus type optical transmission line network, an optical branching device having an optical repeater for amplifying an attenuated optical signal and a switch for switching the transmission line of the optical signal is required.

FIG. 6 is a block diagram showing a configuration example of a conventional optical branching device.

In the figure, the optical cable 61 _1, 61 ₃ as a main line, an optical fiber 52 _1, 52 ₄ and constituted by the feed line 59 _1, 59 _2.
The optical cable 61 _{2 serving as a} branch line is composed of optical fibers 52 ₂ and 52 ₃ .

Optical branching device 60 includes a photoelectric conversion circuit 53 and 55 for converting an optical signal inputted from the optical fiber 52 _1, 52 ₃ into an electric signal,
The electro-optical conversion circuits 54 and 56 that convert the electric signals output to the optical fibers 52 ₂ and 52 ₄ into optical signals, and the branch paths or the optical paths that connect the optical fibers 52 ₂ and 52 ₃ to the optical fibers 52 ₁ and 52 ₄ , respectively. An electrical processing circuit 58 that switches the short-circuit path that connects the fiber 52 ₁ and the optical fiber 52 ₄ and that further performs amplification and other processing, and a power supply circuit 57 that supplies the power supplied from the power supply line 59 to each circuit. Equipped with.

The optical branching device 60 is usually used as an optical signal branching unit of an optical transmission line network in which a branch line is connected to a trunk line to form a bus type optical transmission line.

Here, when a cut other faults in the optical cable 61 ₂ which is a branch occurs, the electrical processing circuit 58, switch to short-circuit path connecting the optical fibers 52 ₁ and the optical fiber 52 _4, the optical cable 61 ₂ The transmission line is switched to disconnect the.

[Problems to be Solved by the Invention]

By the way, for example, in a submarine repeater transmission line network using a submarine optical cable, an optical branching device required when constructing a bus type or star type optical transmission line network must operate without maintenance for a long period of time. High reliability is required. However, in the conventional optical branching device, many components including semiconductor elements are used in each circuit, and in order to secure the reliability required for the optical branching device, the reliability of each of the many components is made extremely high. However, the optical branching device was expensive.

Further, since the landing station normally monitors the transmission path, it is necessary to separately secure a transmission path for transmitting control information for switching the transmission path.

The present invention solves such a conventional problem, and provides an optical branching device that optically controls switching of optical signal transmission lines, and an optical transmission line network using the optical branching device. Has an aim.

[Means for solving the problem]

FIG. 1 is a principle block diagram of the optical branching device according to the first aspect.

In the figure, connected to a trunk line, a trunk line optical signal input / output unit for inputting and outputting an optical signal of a first wavelength, and a branch line,
Branch line optical signal input / output section for inputting / outputting optical signals dropped / added to / from the trunk line, branch path connecting the trunk line optical signal input / output section and branch line optical signal input / output section, and trunk line optical signal In a light branching device provided with a branching means for switching between a short-circuit path connecting between the input and output parts, a control light input part to which control light of a second wavelength different from the first wavelength is inputted via a branch line. The branching means includes an optical branching element for branching an optical signal from the trunk optical signal input / output section into a branch path and a short circuit path, and sending an optical signal from the branch path or the short circuit path to the trunk optical signal input / output section. , Driven by the power supplied from the main line, and a pumping light source that generates pumping light of a predetermined wavelength, and is inserted into the short-circuit path, enters the pumping state by the incidence of the pumping light, and emits light according to the incidence of the control light. It is equipped with an optical amplification element that controls signal amplification. It is.

FIG. 2 is a block diagram of the principle of the optical transmission line network according to the second aspect.

In the figure, a bus-shaped main line including an optical fiber for transmitting an optical signal of a first wavelength and a power supply line for supplying electric power, and a main line terminal unit provided at both ends of the main line for transmitting / receiving transmission information and supplying electric power. And a branch line branched from a bus-shaped trunk line, including a branch line including an optical fiber for returning and transmitting an optical signal that is branched and inserted between the trunk line, and a branch line terminal portion for extracting and inserting transmission information at the end of this branch line, In an optical transmission line network comprising optical signal branching means for branching and short-circuiting an optical signal at a connection between a trunk line and a branch line, the optical signal branching means is constituted by the optical branching device according to claim 1, and a branch line end. A control light source for generating control light of the second wavelength is installed in the local portion, and the branch line is configured to transmit an optical signal and control light.

Further, the optical branching device according to claim 3 is connected to the trunk line and connected to the trunk line optical signal input / output unit for inputting / outputting the optical signal of the first wavelength and the branch line, and added / dropped between the trunk line. A branch optical signal input / output unit for inputting / outputting an optical signal, a branch path connecting the trunk optical signal input / output unit and the branch optical signal input / output unit, and the trunk optical signal input / output unit are connected. In an optical branching device having a branching means for switching between a short-circuit path and a branching means, a branching means is provided with a control light input section for receiving control light of a second wavelength different from the first wavelength, and the branching means is a trunk line. An optical branching element for branching an optical signal from the optical signal input / output section into a branch path and a short-circuit path, and sending an optical signal from the branch path or the short-circuit path to the trunk optical signal input / output section, and being inserted in the branch path, The pump light enters from the branch line optical signal input / output section The first optical amplification element that amplifies the signal and the excitation light that is inserted into the short-circuit path and enters from the main optical signal input / output unit enters the excited state, and the amplification control of the optical signal is performed according to the incidence of the control light. And a second optical amplification element.

The optical transmission line network according to claim 4 is a bus-shaped trunk line including an optical fiber that transmits an optical signal of a first wavelength, and trunk line ends that are provided at both ends of the trunk line and that transmit and receive transmission information. A local line, a branch line branched from a bus-like main line, and a branch line including an optical fiber for returning and transmitting an optical signal dropped and inserted between the trunk line, and a branch line terminal unit for extracting and inserting transmission information at the end of this branch line. In an optical transmission line network including an optical signal branching unit for branching and short-circuiting an optical signal at a connection portion between a trunk line and a branch line, the optical signal branching unit is configured by the optical branching device according to claim 3, and the trunk line A pumping light source for generating pumping light is installed in the terminal section, and a control light source for generating control light of the second wavelength and a pumping light source for pumping light are installed in the branch line terminal section. However, the trunk line is configured to transmit optical signals and pumping light. The branch line is configured to transmit an optical signal, pumping light, and control light, and the pumping light to be incident on the first optical amplification element of the optical branching device is branched from the pumping light source at the branch line terminal part via the branch line. The pumping light that enters the branch optical signal input / output unit of the device and enters the second optical amplification element is for the pumping light of the pumping light source of the trunk line terminal local area through the trunk line and for the pumping light of the adjacent branch line terminal local area. The light source is made to enter the trunk optical signal input / output unit through the branch line, the optical branching device, and the trunk line.

[Action]

According to the optical branching device of the first aspect, a branching route and a short-circuiting route that are processed by an optical signal as they are are formed via the optical branching device and the optical amplifying device.

Here, the optical amplification element inserted in the short-circuit path amplifies the input optical signal by being excited by the excitation light, and its gain is controlled by the control light (OFC'89 POS
TDEADLINE PAPER THURSDAY, FEBRUARY 9,1989, PD15 "A 21
2km NON-REPETED Er + 3 DOPEDFIBER AMPLIFIERS IN AN
IM / DIRECTDETECTION REPETER SYSTEM "K.HAGIMOTO and others).

That is, when the branch line is normally connected and the control light is input, the optical amplification element is brought into an output saturation state by the control light, the gain of the optical signal is almost lost, and the transmission path by the branch path is formed. Further, when the input of the control light with the branch line cut off is interrupted, the optical amplification element amplifies the optical signal, and a transmission path is formed by the short-circuit path.

As described above, the optical branching device according to the first aspect can directly perform automatic switching and amplification of the transmission line as an optical signal.

An optical transmission line network according to a second aspect uses the optical branching device according to the first aspect as an optical signal branching means of a bus type optical transmission line network, and the optical branching device is provided with a control provided at a branch line terminal portion. With the configuration in which the control light is taken in from the light source for light via the optical fiber of the branch line, it is possible to automatically switch to the short-circuit path due to the cutting of the branch line, for example. In addition, the switching and amplification of the optical signal on the transmission line can be processed without changing the optical signal.

The optical branching device according to claim 3 supplies the pumping light from the outside (main line and branch line) together with the optical signal, while the optical branching device according to claim 1 includes the pumping light source therein. A first optical amplification element and a second optical amplification element for amplifying an optical signal by pumping light are respectively provided in the branch path and the short circuit path, and the control light is taken into the second amplification element. .

Therefore, when the branch line is properly connected,
Since the pump light is supplied from the branch line to the first optical amplifier element, the pump light is supplied from the trunk line to the second optical amplifier element, and the control light that creates the output saturation state is supplied from the branch line, the same. Then, a transmission path is formed by the branch path.

On the other hand, when the branch line is disconnected, the pumping light is not supplied to the first optical amplifier element, the function as the optical amplifier element is stopped, and the pumping light is supplied from the main line. Since the control light is not incident on the optical amplification element, a transmission path by a short circuit path is similarly formed.

That is, in the optical branching device according to the third aspect, the automatic switching and amplification of the transmission line can be directly performed as an optical signal.

An optical transmission line network according to a fourth aspect uses the optical branching device according to the third aspect as an optical signal branching means of a bus type optical transmission line network, and the optical branching device includes a trunk line terminal unit and a branch line terminal unit. The excitation light is taken in from the provided excitation light source through the trunk line and the branch line, and the control light is taken in from the control light source provided at the branch line terminal by the branch line. It becomes possible to automatically switch to the short-circuit path due to disconnection. In addition, the switching and amplification of the optical signal on the transmission line can be processed without changing the optical signal.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a block diagram showing the configuration of an embodiment of the optical branching device described in claim 1.

In the figure, an optical branching device of the present embodiment is provided with an optical signal input terminal 11, an optical signal output terminal 15, and an optical signal transmission terminal serving as a branch line, which are respectively connected to optical fibers for optical signal transmission 33 ₀ and 33 ₁ which are main lines. It has an optical signal output terminal 13 and an optical signal input terminal 14 connected to the optical fibers 35 ₀ and 35 _{1, respectively} , and switches the optical signal transmission path between a branch path and a short circuit path.

An optical signal having a wavelength of 1.55 [μm] input from the optical signal input terminal 11 is output in two directions via the optical divider 21.

One of the optical signals passes through the pumping optical multiplexer 22 and is output to the optical signal output terminal 13 via the erbium-doped fiber 23 and the 1.55 μm wavelength optical pass filter 24 ₁ .

Further, the optical signal input from optical signal input terminal 14, the wavelength 1.55μm light pass filter 24 _2, through the erbium-doped fiber 25, is further input through the pumping light multiplexer 26 to the optical coupler 27, optical It is output to the signal output terminal 15.

The other optical signal output from the optical divider 21 has a wavelength of 1.
Through 55μm light pass filter 24 _3, and enters further into the erbium doped fiber 29 through a control light multiplexer 28. The optical signal emitted from the erbium-doped fiber 29 passes through the pump optical multiplexer 30, is input to the optical coupler 27 via the 1.55 μm wavelength pass filter 31, and is output to the optical signal output terminal 15.

The semiconductor laser 37 supplied with power from the power supply terminal 12 connected to the power supply line 34 _{0 of the} main line and the power supply terminal 16 connected to the power supply line 34 ₁ outputs excitation light having a wavelength of 1.48 [μm]. This pumping light is transmitted through the optical divider 38 to the pumping light multiplexer.
It is incident on 22, 26, 30 and is reflected by each and incident on the corresponding erbium-doped fiber 23, 25, 29.

In addition, the wavelength of 1.53 that is input from the control light input terminal 17 that is connected to the control light transmission optical fiber 36 that is installed with the branch line
The control light of [μm] is reflected by the control light multiplexer 28 and enters the erbium-doped fiber 29.

Here, the correspondence between the principle block diagram of the present invention shown in FIG. 1 and the configuration diagram of the embodiment shown in FIG. 3 is shown.

The pumping light source is a semiconductor laser 37, the optical branching element is an optical divider 21 and an optical coupler 27, the optical amplifying element is an erbium-doped fiber 29, and the trunk optical signal input / output unit is an optical signal input terminal 11 and an optical signal. Signal output terminal 15,
The branch optical signal input / output unit is an optical signal output terminal 13 and an optical signal input terminal 14, and the control light input unit is a control light input terminal 17. In this embodiment, the erbium-doped fibers 23 and 25 are inserted in the branch path, but this is for performing optical amplification of the branch optical signal according to the length of the branch and other conditions. The optical branching device is not necessarily required.

Further, the optical divider 38, the pumping light multiplexers 22, 26, 30 and the control light multiplexer 28 are configured to efficiently enter the optical signal and the pumping light or the control light into the erbium-doped fibers 23, 25, 29. is there. Further, the 1.55 μm wavelength light pass filters 24 _{1 to} 24 ₃ block the excitation light emitted from the erbium-doped fiber 29, and the 1.55 μm wavelength light pass filter 31
Controls the control light emitted from the erbium-doped fiber 29.

The erbium-doped fiber 29 has a pumping light (wavelength 1.48).
[Μm]) enters the excited state and the optical signal (wavelength
1.55 [μm]) and the control light (wavelength 1.53 [μm]) are amplified, but the control light causes an output saturation state, and there is almost no gain for the optical signal. That is, apparently, the optical signal transmitting optical fiber 33 ₀ and the optical signal transmitting optical fiber 33 ₁ are in a disconnected state.

On the other hand, the erbium beep fibers 23 and 25, which are excited by the incidence of pumping light (wavelength 1.48 [μm]), amplify the optical signal.
_0, 33 to _1, the optical signal transmission optical fiber 35 ₀ as a branch, 35 ₁
It is possible to form a bus-type transmission path to which is connected.

When the input of the control light from the control optical transmission optical fiber 36 is stopped, the erbium-doped fiber 29 is no longer in a saturated state, so that the optical signal that passes through the control optical multiplexer 28 and is incident is amplified and emitted. The emitted optical signal is pumped by an optical multiplexer 3
0, wavelength 1.55 μm optical pass filter 31, optical coupler 27, and optical signal output terminal 15 through the optical signal transmission optical fiber
33 are output to _1, it can be an optical signal transmission optical fiber 33 ₀ and an optical signal transmission optical fiber 33 ₁ in the main line to form a short circuit path connected.

FIG. 4 is a block diagram showing the configuration of an embodiment of the optical branching device described in claim 3.

The same parts as those of the optical branching device shown in FIG. 3 are designated by the same reference numerals, and their description will be omitted.

A feature of this embodiment is that the pumping light (wavelength 1.48 [μm]) supplied to each erbium-doped fiber 23, 25, 29 in the optical branching device serves as a trunk optical fiber for optical signal transmission 33 ₀ , 33 ₁ and the optical fibers for transmitting optical signals 35 ₀ and 35 _{1 serving as} branch lines, which are wavelength-multiplexed and incident on the optical signal (wavelength 1.55 [μm]), and the pumping light source (semiconductor laser 37) is placed therein. It is in a configuration that does not have. That is, the light source for pumping light is a trunk line terminal part connected to the optical signal transmission optical fibers 33 ₀ and 33 _{1 serving} as trunk lines and a branch line terminal connected to the optical signal transmission optical fibers 35 ₀ and 35 _{1 serving} as branch lines. It is provided locally.

Further, in this embodiment, the control light (wavelength 1.53 [μm]) for controlling the erbium-doped fiber 29 in the short circuit path is also wavelength-multiplexed from the optical signal transmitting optical fiber 35 _{1 serving} as the branch line to the optical signal and the pumping light. It shall be incident. Therefore, in this embodiment, the control light input section and the branch optical signal input / output section according to claim 3 are the same, and the optical filter 70 that separates only the control light and makes it enter the control optical multiplexer 28 is the optical signal input. It is configured to be inserted between the terminal 14 and the erbium-doped fiber 25.

With such a configuration, in a normal time (when the branch line is not damaged), the erbium-doped fibers 23 and 25 inserted in the branch path are separated from the optical signal transmitting optical fibers 35 ₀ and 35 _{1 serving as} branch lines. Excitation light supplied (wavelength 1.48 [μ
m]), the optical signal of the branch path (wavelength 1.55 [μm])
Is being amplified.

Further, the erbium-doped fiber 29 inserted in the short-circuit path, the residual portion of the pumping light supplied to the erbium-doped fiber of the other adjacent optical branching device, and the pumping light emitted from the trunk line terminal is the light that becomes the trunk line. is supplied through the signal transmission optical fiber 33 _0, 33 _1, performs the amplifying operation on the optical signal of the short-circuit path (wavelength 1.55 [μm]), at the same time the control light (wavelength 1.53 [μm]) is an optical filter 70, incident on the erbium-doped fiber 29 through the control optical multiplexer 28,
Similarly, it operates to block the optical signal.

On the other hand, if a disconnection failure occurs in the optical signal transmission optical fibers 35 ₀ and 35 ₁ that become a branch line, and the optical signal, the control light and the pump light supplied from the branch line terminal to the optical branching device are cut off,
The excitation light is not supplied to the lerbium-doped fibers 23 and 25, and the optical signals are almost cut off. Also,
The control light is not supplied to the erbium-doped fiber 29, but since the pumping light is supplied from the optical signal transmitting optical fibers 33 ₀ and 33 ₁ which are the trunk lines, it functions as an optical amplifying element for the optical signal, and the short circuit path is formed. It is formed.

FIG. 5 is a block diagram showing the configuration of an embodiment of the optical transmission line network according to the present invention.

The present embodiment shows a bus-type submarine optical transmission line network for transmitting an optical signal having a wavelength of 1.55 [μm], and the optical branching device used is the optical branching device shown in FIG. , 4th
The same applies when the optical branching device shown in the figure is used.

In FIG. 5, the landing station 40 ₁ and the landing station 40 ₂ are
An optical signal transmission optical fiber 33 _{0-33 2} and the power supply line 34 _{0-34 2} as a main line, are connected via the optical branching device 44 _1, 44 _2. Optical branching device 44 _1, 44 _2, the optical signal transmission optical fiber 35 _{0-35 3} serving as a branch, control light transmission optical fiber 36 _1, 3
Landing stations 40 ₃ and 40 ₄ are connected via 6 ₂ . In addition, here, for ease of explanation, it is assumed that the optical signal is transmitted from the landing station 40 ₁ to the landing station 40 ₂ .

The landing station 40 ₁ includes a transmission terminal device 41 which outputs an electric signal obtained by converting information to be transmitted into a transmission path code, and an optical signal transmission optical fiber 33 which converts the electric signal into an optical signal having a wavelength of 1.55 [μm]. It comprises an electric-optical conversion circuit 42 to be output to _0, and a power supply circuit 43 connected to the feed line 34 _0.

The landing station 40 ₂ extracts the information transmitted from the photoelectric conversion circuit 49 that converts the optical signal of wavelength 1.55 [μm] input from the optical fiber 33 ₂ for transmitting an optical signal into an electrical signal. A transmission terminal device 50 and a power supply circuit 51 connected to the power supply line 34 ₂ are provided.

Landing stations 40 ₃ and 40 ₄ are optical fibers for optical signal transmission 35 ₀ and 3
Optical-electrical conversion circuits 46 ₁ and 46 ₂ for converting an optical signal having a wavelength of 1.55 [μm] input from 5 ₂ into an electrical signal, and information for extracting the information transmitted from this electrical signal and inserting the information to be transmitted. An extraction / insertion unit 47 ₁ , 47 ₂ and an electro-optical conversion circuit 48 ₁ for converting the electric signal into which the information has been extracted and inserted into an optical signal having a wavelength of 1.55 [μm] and outputting it to the optical fibers for optical signal transmission 35 ₁ , 35 _3. , 48 ₂ and.

Further, as a characteristic configuration of the present invention described in claim 2, control light having a wavelength of 1.53 [μm] is generated in the landing stations 40 ₃ and 40 ₄ , and control optical transmission optical fibers 36 ₁ and 36 _{2 are used.} Control light sources 45 ₁ and 4 for sending to the respective optical branching devices 44 ₁ and 44 ₂ via
5 ₂ are equipped.

Here, the correspondence between FIG. 2 and FIG. 5 is shown. The trunk line terminal stations are the landing stations 40 ₁ and 40 ₂ , and the branch line terminal stations are the landing stations 40 ₁ .
_3, a 40 _4, an optical signal branching means is an optical branching device 44 _1, 44 _2, the control light source is a control light source 45 _1, 45 _2.

By controlling light having a wavelength of 1.53 [μm] is input to the optical branching device 44 _1, 44 _2, optical signal transmission optical fiber 33 ₀ and an optical signal transmission optical fiber 33 _1, the optical signal transmission optical fiber 33 ₁
Optical signal transmission optical fiber 33 ₂ is apparently cut branch path is formed with.

Optical fiber for optical signal transmission from the landing station 40 ₁ on the transmitting side 33 ₀
The optical signal sent to the optical fiber is output to the optical signal transmitting optical fiber 35 ₀ via the optical branching device 44 ₁ and transmitted to the landing station 40 ₃ . The landing station 40 ₃ extracts and inserts the information to be transmitted through the photoelectric conversion circuit 46 ₁ and the information extraction / insertion unit 47 _1, and the wavelength of the optical / optical conversion circuit 48 _{1 is} again 1.55 [μm].
The optical signal is transmitted to the optical branching device 44 ₁ through the optical signal transmitting optical fiber 35 ₁ . This optical signal is output from the optical branching device 44 ₁ to the optical signal transmitting optical fiber 33 ₁ .

In the same manner, the optical signal transmitted to the optical branch device 44 ₂ is transmitted to the landing station 40 ₂ on the reception side through the landing stations 44 ₄ and the optical signal transmission optical fiber 33 _2.

Here, for example, when the submarine optical cable including the optical signal transmitting optical fibers 35 ₀ and 35 ₁ and the control optical transmitting optical fiber 36 ₁ between the optical branching device 44 ₁ and the landing station 40 ₃ is disconnected, supply of the control light is stopped in the branch unit 44 _1. As a result, the optical branching device 44 ₁ can form a short circuit path connecting the optical signal transmitting optical fibers 33 ₀ and 33 ₁ as described above, and can disconnect the landing station 40 ₃ .

In this way, even if the submarine cable of the branch line is cut, the transmission path can be automatically switched.

In the optical transmission line network according to claim 4, the landing station 40
₁ to 40 ₄ is equipped with a pumping light source for generating pumping light having a wavelength of 1.48 [μm], and the landing stations 40 ₃ and 40 ₄ are equipped with a wavelength of 1.
Equipped with a control light source for generating 53 [μm] control light,
Each is configured to be transmitted to the optical branching device via a predetermined optical fiber (optical signal transmitting optical fiber for wavelength-multiplexing an optical signal in the above-described embodiment), and other configurations and operations are the same. Explained.

In addition, although the bus type optical transmission line network has been described in the present embodiment, the same optical branching device and optical transmission line network can be configured in the star type optical transmission line network.

〔The invention's effect〕

As described above, in the optical branching device according to claim 1,
The branch path or short-circuit path of the transmission line can be automatically switched, and the switching process and amplification process can be performed with the optical signal as it is, which is excellent in stability and electric circuit parts. Since it is possible to significantly reduce the cost, it is possible to provide an economical and highly reliable optical branching device.

Further, in the optical transmission line network according to claim 2, the optical branching device of the present invention is used in a bus type optical transmission line, and the control light is branched by an optical fiber provided as an optical fiber for optical signal transmission serving as a branch line. By transmitting the data to the branch, it is possible to easily disconnect the branch line or other failures.

Further, in the optical branching device according to claim 3 and the optical transmission line network according to claim 4, the pumping light source of the optical branching device is further unnecessary, and the reliability can be improved with the reduction of the number of parts. .

As described above, since a highly reliable optical transmission line network can be constructed, it is possible to suppress the non-operation rate of the entire transmission line network to a low level. Further, when applied to a submarine optical transmission line network, the installation work can be simplified by downsizing the optical branching device.

Moreover, it is considered that such an optical branching device and an optical transmission line network are effectively applied to a coastal route or a large-scale optical LAN on the seabed or on land.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the invention of claim 1. FIG. 2 is a principle block diagram of the invention of claim 2. FIG. 3 is a configuration block diagram of an embodiment of the optical branching device according to claim 1. FIG. 4 is a configuration block diagram of an embodiment of the optical branching device according to claim 3. FIG. 5 is a block diagram of an embodiment of the optical transmission line network according to claim 2. FIG. 6 is a block diagram showing a configuration example of a conventional optical branching device. 11,14 …… Optical signal input terminal, 12,16 …… Power supply terminal, 13,
15 …… Optical signal output terminal, 17 …… Control light input terminal, 21, 38
...... Optical divider, 22, 26, 30 …… Excitation optical multiplexer, 23, 2
5,29 …… Erbium-doped fiber, 24,31 …… wavelength
1.55μm light pass filter, 27 …… optical coupler, 28 ……
Control optical multiplexer, 33, 35 ... Optical fiber for optical signal transmission, 34
...... Feed line, 36 ...... Control optical transmission optical fiber, 37 ...... Semiconductor laser, 40 ...... Landing station, 41,50 ...... Transmission terminal equipment, 42,48 ...... Electro-optical conversion circuit, 43,51 , 57 …… power supply circuit, 44, 60 …… optical branching device, 45 …… control light source, 46,
53, 55 ...... photoelectric conversion circuit, 47 ...... information extraction insertion section, 5
4, 56 …… electro-optical conversion circuit, 58 …… electric processing circuit, 61…
… Optical cable, 70… Optical filter.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G02F 1/35 501 (56) References JP-A-60-190040 (JP, A) JP-A-62 -102635 (JP, A) JP 63-6926 (JP, A) JP 63-253926 (JP, A)

Claims (4)

[Claims] 1. A trunk optical signal input / output unit connected to a trunk line for inputting / outputting an optical signal of a first wavelength; and an optical signal connected / branched to a branch line for input / output of an optical signal. A branch optical signal input / output section, a branch path connecting the trunk optical signal input / output section and the branch optical signal input / output section, and a short-circuit path connecting the trunk optical signal input / output sections. In the optical branching device including a branching unit, a control light input unit to which control light of a second wavelength different from the first wavelength is input via the branch line, the branching unit is the trunk line light. An optical branching element for branching an optical signal from the signal input / output unit into the branch path and the short circuit path, and sending an optical signal from the branch path or the short circuit path to the trunk optical signal input / output section; Driven by electric power And a light amplification element that is inserted into the short-circuit path, is in a pumped state when the pumping light is incident, and performs amplification control of the optical signal according to incidence of the control light. Optical branching device. 2. A bus-shaped main line including an optical fiber for transmitting an optical signal of a first wavelength and a power supply line for supplying electric power, and main lines provided at both ends of the main line for transmitting / receiving transmission information and supplying electric power. A terminal line, a branch line branched from the bus-like trunk line, and a branch line including an optical fiber for branching and transmitting an optical signal branched and inserted between the trunk line, and a branch line end for extracting and inserting transmission information at the end of this branch line. In an optical transmission line network comprising a local portion and an optical signal branching unit for branching and short-circuiting an optical signal at a connection between the trunk line and a branch line, the optical signal branching unit is the optical branching device according to claim 1. A light source for control light that generates control light of a second wavelength is installed in the branch line terminal portion, and the branch line is configured to transmit an optical signal and control light. network. 3. A trunk line optical signal input / output unit connected to the trunk line for inputting / outputting an optical signal of a first wavelength, and an optical signal connected to a branch line for branching / inserting into / from the trunk line. A branch optical signal input / output section, a branch path connecting the trunk optical signal input / output section and the branch optical signal input / output section, and a short-circuit path connecting the trunk optical signal input / output sections. In the optical branching device including a branching unit, a control light input unit to which control light of a second wavelength different from the first wavelength is input via the branch line, the branching unit is the trunk line light. An optical branching element for branching the optical signal from the signal input / output unit into the branch path and the short-circuit path, and sending the optical signal from the branch path or the short-circuit path to the trunk optical signal input / output section, and the branch path Inserted and incident from the branch optical signal input / output unit A first optical amplifier element that is in an excited state by the excitation light and amplifies the optical signal, and is inserted into the short-circuit path, is in an excited state by the excitation light incident from the main line optical signal input / output unit, and is the control light. And a second optical amplification element that controls the amplification of the optical signal in accordance with the incidence of light. 4. A bus-shaped main line including an optical fiber for transmitting an optical signal of a first wavelength, main line terminal units provided at both ends of the main line for transmitting and receiving transmission information, and from the bus-shaped main line. A branch line that includes an optical fiber that branches and inserts an optical signal back and forth between the branch line and the trunk line, a branch line terminal unit that extracts and inserts transmission information at the end of this branch line, and the connection between the trunk line and the branch line In an optical transmission line network including an optical signal branching unit for branching and short-circuiting an optical signal in a section, the optical signal branching unit is configured by the optical branching device according to claim 3, and in the trunk terminal unit, A pumping light source for generating pumping light is installed, and the branch line terminal is provided with a control light source for generating control light of a second wavelength and a pumping light source for generating pumping light. Is a configuration for transmitting an optical signal and pumping light Yes, the branch line is a configuration for transmitting an optical signal, a pumping light and a control light, the pumping light to be incident on the first optical amplification element of the optical branching device, from the pumping light source of the branch line terminal part The pumping light that enters the branch line optical signal input / output unit of the optical branching device through the branch line and enters the second optical amplification element is supplied from the pumping light source of the trunk line terminal unit through the trunk line, and adjacently. An optical transmission line network characterized in that the pumping light source at the branch line terminal portion is made to enter the trunk line optical signal input / output unit through the branch line, the optical branching device, and the trunk line.